these are city buses. and then we have a nation buster which is going to come grazing past the earth and may even hit the earth. that's called the asteroid apofet. it's ten times bigger than the asteroid that scimed the earth last week. >> stephen: what do you mean may hit? what is the -- do the math. [ laughter ] what is the math on that one? >> well, first it's going to skim by the earth in 2029 and it's going to graze the atmosphere. that's the question mark. we don't know how much friction it's going to encounter. that cannot be factored relyibly. when it grazes the atmosphere on the second pass in 2036 there's a window of opportunity where the thing could actually hit the earth even though it's still very small. >> stephen: because of the friction it encounters on 2029. >> that's right in the second pass. >> stephen: can we lubricate the earth in some way so there's not so much friction? [cheers and applause] and just duz -- [cheers and applause] >> the russians have taken this seriously. >> stephen: